Generally, compressors for compressing refrigerant in air conditioning systems for vehicles have been developed in various forms. Following the recent trend of using electric apparatuses as parts of vehicles, development of an electric compressor which is operated with electricity using a motor has become appreciably more active.
The motor of the electric compressor is typically configured to be adjusted in output by an inverter. However, because the electric compressor is operated with electricity, the motor and the inverter constituting the electric compressor generate heat, and the generated heat significantly affects the performance of the motor and the inverter. In an effort to overcome such a heating problem, various alternatives have been introduced.
With regard to cooling of the motor, a configuration is typically employed, in which refrigerant to be compressed directly flows around a portion of a main housing in which the motor is disposed, and thus absorbs heat generated from the motor.
However, in the case of cooling of the inverter, a plurality of heat-generating switching elements (hereinafter, referred to as inverter elements) such as IGBTs (insulated gate bipolar mode transistors) are included in the inverter. Because such inverter elements have low durability, a method of cooling the inverter elements by making refrigerant flow directly therearound in a similar manner to that of the cooling of the motor is not preferable.
A conventional inverter element installation structure will be described with reference to the related drawings.
Referring to FIGS. 1 to 2, a plurality of inverter elements 2 are mounted on a seating surface 1a in an inverter housing 1 in such a way that one surface of each inverter element 2 faces the seating surface 1a. The inverter housing 1 is configured to come into close contact with a suction chamber (not shown) formed in a main housing 4 so that heat generated from each inverter element 2 is conducted to the suction chamber of the main housing 4 through the one surface of the inverter element and the inverter housing 1, and heat generated from the other surface of each inverter element 2 is transferred to air in the inverter housing 1 by convection.
However, in the shown configuration, heat generated from each inverter element 2 is transferred to the inverter housing 1 by conduction only through the one surface of the inverter element 2, that is, through the surface of the inverter element 2 that is attached to the seating surface 1a of the inverter housing 1. Otherwise, heat is transferred from each inverter element 2 to air in the inverter housing 1 by convection. Therefore, heat generated from the inverter elements 2 cannot be effectively dissipated. Consequently, the overall efficiency of the inverter is reduced, and a serious problem of the inverter element 2 being even damaged by overheating may be caused.
Furthermore, when the plurality of inverter elements 2 are mounted on the seating surface 1a, there is the need for a separate jig to be used to individually set the locations of the inverter elements 2. Therefore, there is a problem in that a process of manufacturing the electric compressor is complicated.